I got it off Using the double sided tape; Thanx Steve!
It turns out that the front ring
was an applique, with the front of the lens barrel underneath. No fasteners are visible; It appears that the bezel surrounding the front lens unscrews, but there is so much varnish on the front of the barrel, and thus in the threads that I haven't yet been able to get it to budge.
It appears to be very similar to this lens, except it has 5 aperture blades instead of seven; an odd number to be sure...
Matt's Classic Cameras: Kalimar Macro f2.8 28mm Pentax KA